High Pressure Heat Treatment – Phase Transformation under Isostatic Pressure in HIP

High Pressure Heat Treatment – Phase Transformation under Isostatic Pressure in HIP

Magnus Ahlfors, Alexander Angré, Dimitris Chasoglou, Linn Larsson

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Abstract. Modern HIP furnaces equipped with forced convection cooling enable very fast cooling rates under isostatic pressure. This does not only give shorter HIP cycles and increased productivity but also allows complete heat treatment cycles to be performed in the HIP unit. It has been shown in previous studies that extreme pressures of several thousand bar can push phase transformation towards longer times for the Fe-C system. The new URQ HIP cooling systems give the opportunity to investigate the impact of pressures up to 2000 bar on phase transformation time dependency. A 4340 steel was used in this study and a comparison of austenite phase transformation time at 100 bar and 1700 bar was performed. The study was performed by isothermal heat treatment of specimens for a specific time followed by quenching. To evaluate the influence of pressure on hardenability, the phase fractions were evaluated using grid method on SEM images. The study found significant influence of HIP pressure on the phase transformation kinetics of the material studied.

Keywords
HIP, High Pressure Heat Treatment, URQ

Published online 2/11/2019, 8 pages
Copyright © 2019 by the author(s)
Published under license by Materials Research Forum LLC., Millersville PA, USA

Citation: Magnus Ahlfors, Alexander Angré, Dimitris Chasoglou, Linn Larsson, High Pressure Heat Treatment – Phase Transformation under Isostatic Pressure in HIP, Materials Research Proceedings, Vol. 10, pp 149-156, 2019

DOI: http://dx.doi.org/10.21741/9781644900031-21

The article was published as article 21 of the book Hot Isostatic Pressing

Content from this work may be used under the terms of the Creative Commons Attribution 3.0 licence. Any further distribution of this work must maintain attribution to the author(s) and the title of the work, journal citation and DOI.

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